1. Field of the Invention
The present invention relates to a coating material for protecting the surfaces of teeth, which has for its main object to protect the surfaces of healthy teeth against an acid etching agent used for dental treatments for preservation and restoration, and for its additional object to prevent the so-called overfilling of a restorative material, in particular, a composite resin.
2. Statement of the Prior Art
For restoration with composite resins, a carious moiety of a tooth is cut out by a dental cutting material to prepare a cavity. Thereafter, the dentin is subjected to partial demineralization with an acid etching agent for rough plasticization at a pre-treatment step for enhancing the adhesion between the dentin and the restorative composite resin, followed by application of a bonding material. However, since the acid etching agent used at such a pre-treatment step is a highly fluid aqueous solution of phosphoric or citric acid, a problem arises that even the healthy enamel surrounding the cavity is subjected to demineralization with the result that the surface of a tooth is made cloudy and rough unnecessarily.
The conventional coating material for protecting the surface of teeth is designed to form a protecting film composed mainly of a copolymer based on vinyl acetate and vinyl chloride. However, such a coating material offers a problem that since the protecting film per se obtained therefrom is soft and easily "extensible" in its nature, it cannot be cut out well by a dental cutting tool at the time of cavity preparation, thus leaving behind an uncut portion and causing refuse to be mingled in the inside of the restorative composite resin at the time of filling. This obstructs the distribution of that coating material. Further, since the coating film is of a dull color tone, it is difficult to distinguish it from the cavity edge. Hence, a coating film of a vivider color tone is still demanded by dentists.